"Some persons suppose that these parasites, which, from their particular form, were called flukes, were the cause of the rot. They are only the effect; yet it is to be remembered that they multiply so rapidly that they become the cause of further diseased action. Sheep, in the earlier stages of the affection, before their biliary ducts become filled with flukes, may be restored; but, when the parasites existed in abundance, there was no chance of the animal's recovery. Those persons who supposed flukes to be the cause of rot had, perhaps, some reason for that opinion. Flukes are oviparous; their ova mingle with the biliary secretion, and thus find their way out of the intestinal canal into the soil; as in the feculent matter of rotten sheep may be found millions of flukes. A Mr. King, of Bath, (England,) had unhesitatingly given it as his opinion that flukes were the cause of rot; believing that, if sheep were pastured on land where the ova existed, they would be taken up with the food, enter into the ramifications of the biliary ducts, and thus contaminate the whole liver. There appeared some ground for this assertion, because very little indeed was known with reference to the duration of life in its latent form in the egg. How long the eggs of birds would remain without undergoing change, if not placed under circumstances favorable to the development of life in a more active form, was undecided. It was the same with the ova of these parasites; so long as they remained on the pasture they underwent no change; but place them in the body of the animal, and subject them to the influence of heat, &c., then those changes would commence which ended in the production of perfect flukes. Take another illustration of the long duration of latent life: Wheat had been locked up for hundreds of years—nay, for thousands—in Egyptian mummies, without undergoing any change, and yet, when planted, had been found prolific.
... He was not, then, to say that rot was in all cases a curable affection; but at the same time he was fully aware that many animals, that are now considered incurable, might be restored, if sufficient attention was given to them. About two years ago, he purchased seven or eight sheep, all of them giving indisputable proof of rot in its advanced stage. He intended them for experiment and dissection; but as he did not require all of them, and during the winter season only he could dissect, he kept some till summer. They were supplied with food of nutritious quality, free from moisture; they were also protected from all storms and changes of weather, being placed in a shed. The result was, that without any medicine, two of these rotten sheep quite recovered; and when he killed them, although he found that the liver had undergone some change, still the animals would have lived on for years. Rot, in its advanced stage, was a disease which might be considered as analogous to dropsy. A serous fluid accumulates in various parts of the body, chiefly beneath the cellular tissue; consequently, some called it the water rot, others the fluke rot; but these were merely indications of the same disease in different stages. If flukes were present, it was evident that, in order to strike at the root of the malady, they must get rid of these entozoa, and that could only be effected by bringing about a healthy condition of the system. Nothing that could be done by the application of medicine would act on them to affect their vitality. It was only by strengthening their animal powers that they were enabled to give sufficient tone to the system to throw off the flukes; for this purpose many advocated salt. Salt was an excellent stimulative to the digestive organs, and might also be of service in restoring the biliary secretion, from the soda which it contained. So well is its stimulative action known, that some individuals always keep salt in the troughs containing the animal's food. This was a preventive, they had good proof, seeing that it mattered not how moist the soil might be in salt marshes; no sheep were ever attacked by rot in them, whilst those sent there infected very often came back free. Salt, therefore, must not be neglected; but then came the question, Could they not do something more? He believed they could give tonics with advantage....
"The principles he wished to lay down were, to husband the animals' powers by placing them in a situation where they should not be exposed to the debilitating effects of cold storms; to supply them with nutritious food, and such as contained but a small quantity of water; and, as a stimulant to the digestive organs, to mix it with salt."
The remarks of Professor S. are valuable to the American farmer. First, because they throw some light on the character of a disease but imperfectly understood; secondly, they recommend a safe, efficient, and common-sense method of treating it; and lastly, they recommend such preventive measures as, in this enlightened age, every farmer must acknowledge to be the better part of sheep doctoring. The reader will easily perceive the reason why the food of sheep is injurious when wet or saturated with its own natural juices, when he learns that the digestive process is greatly retarded, unless the masticated food be well saturated with the gastric fluid. If the gastric fluid cannot pervade it, then fermentation takes place; by which process the nutritive properties of the food are partly destroyed, and what remains cannot be taken up before it passes from the vinous into the acetous or putrefactive fermentation; the natural consequence is, that internal disease ensues, which often gravitates to the feet, thereby producing rot. This is not all. Such food does not furnish sufficient material to replenish the daily waste and promote the living integrity. In short, it produces debility, and debility includes one half the causes of disease. It must be a matter of deep interest to the farmer to know how to prevent disease in his flock, and improve their condition, &c.; for if he possessed the requisite knowledge, he would not be compelled to offer mutton at so low a rate as from three to four cents a pound, at which price it is often sold in the Boston market. We have already alluded to the fact that neat cattle can, with the requisite knowledge, be improved at least twenty-five per cent.; and we may add, without fear of contradiction, that the same applies to sheep. If, then, their value can be increased in the same ratio as that of other classes of live stock, how much will the proprietors of sheep gain by the operation? Suppose we set down the number of sheep in the United States at twenty-seven millions,—which will not fall far short of the mark,—and value them at the low price of one dollar per head: we get a clear gain, in the carcasses alone, of six millions seven hundred and fifty thousand dollars. The increase in the quantity, and of course in the value, of wool would pay the additional expenses incurred. It is a well-known fact that, when General Washington left his estate to engage in the councils of his country, his sheep then yielded five pounds of wool. At the time of his return, the animals had so degenerated as to yield but two and a half pounds per fleece. This was not altogether owing to the quality of their food, but in part to want of due care in breeding.
It is well known that many diseases are propagated and aggravated through the sexual congress; and no matter how healthy the dam is, or how much vital resistance she possesses,—if the male be weak and diseased, the offspring will be more or less diseased at birth. (See article Breeding.)
Dr. Whitlaw observes, "The Deity has given power to man to ameliorate his condition, as may be truly seen by strict attention to the laws of nature. An attentive observer may soon perceive, that milk, butter, and meat, of animals that feed on good herbage, in high and dry soils, are the best; and that strong nourishment is the produce of those animals that feed on bottom land; but those that feed on a marshy, wet soil produce more acrid food, even admitting that the herbage be of the bland and nutritious kind; but if it be composed in part of poisonous plants, the sheep become diseased and rotten, much more so than cattle, for they do not drink to the same degree, and therefore (particularly those that chew the cud) are not likely to throw off the poison. Horses would be more liable to disease than cattle were it not for their sagacity in selecting the wholesome from the poisonous herbage.
"A great portion of the mutton slaughtered is unfit for food, from the fact that their lungs are often in a state of decomposition, their livers much injured by insects, and their intestines in a state of ulceration, from eating poisonous herbs."
Linnæus says, "A dry place renders plants sapid; a succulent place, insipid; and a watery place, corrosive."
One farmer, in the vicinity of Sherburne, (England,) had, during the space of a few weeks, lost nearly nine hundred sheep by the rot. The fear of purchasing diseased mutton is so prevalent in families, that the demand for mutton has become extremely limited.
In the December number of the London Veterinarian we find an interesting communication from the pen of Mr. Tavistock, V. S., which will throw some light on the causes of disease in sheep. The substance of these remarks is as follows: "On a large farm, situated in the fertile valley of the Tavey, is kept a large flock of sheep, choice and well bred. It is deemed an excellent sheep farm, and for some years no sheep could be healthier than were his flock. About eighteen months ago, however, some ewes were now and then found dead. This was attributed to some of the many maladies sheep-flesh is 'heir to,' and thought no more about. Still it did not cease; another and another died, from time to time, until at length, it becoming a question of serious consequence, my attention was called to them. I made, as opportunities occurred, minute post mortem examinations. The sheep did not die rapidly, but one a week, and sometimes one a fortnight, or even three weeks. No previous illness whatever was manifested. They were always found dead in the attitude of sleep; the countenance being tranquil and composed, not a blade of grass disturbed by struggling; nor did any circumstance evidence that pain or suffering was endured. It was evident that the death was sudden. We fancied the ewes must obtain something poisonous from the herbage, and the only place they could get any thing different from the other sheep was in the orchards, since there the ewes went at the lambing time, and occasionally through the summer. But so they had done for years before, and yet contracted no disease. Well, then, the orchards were the suspected spots, and it was deemed expedient to request Mr. Bartlett, a botanist, to make a careful examination of the orchards, and give us his opinion thereon. The following is the substance of his report:—